CO2 reforming of methane over activated carbon-Ni/MgO-Al2O3 composite catalysts for syngas production

The composite catalysts AC-Ni/MgO-Al2O3 were prepared by the co-precipitation method with activated carbon (AC) and [Ni,Mg,Al]-hydrotalcite as the precursors, and characterized by XRD, TG-DTG, N-2 adsorption, H-2-TPR and SEM, respectively. The resultant catalysts were examined for CO2 reforming of methane. The results showed that the introduction of AC into Ni/MgO-Al2O3 catalyst improved the textural properties, especially the surface area and pore volume of mesopores, and decreased the size of metal Ni. Compared with Ni/MgO-Al2O3, the composite AC-Ni/MgO-Al2O3 exhibited higher catalytic activity, stability and H-2/CO ratio. But the AC content obviously influenced the catalytic performances. High AC loading resulted in the decline of catalytic activity owing to lower surface area and fewer active Ni content in the catalyst. 10AC-Ni/MgO-Al2O3 with 10% AC displayed the best catalytic activity and stability compared with Ni/MgO-Al2O3. About 86.2% conversion of CH4, 91.3% conversion of CO2 and above 0.95 ratio of H-2/CO were achieved over 10AC-Ni/MgO-Al2O3 sample for the reaction time of 5430 min. This work provides a route to improve catalytic performances of Ni-based catalysts in CO2 reforming of methane.